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Rhizopus was prevalent in some cultigens, and those experimental runs with high Rhizopus incidence were removed from analyses. Lines evaluated for fruit resistance were also evaluated using leaf assays to determine correlations between fruit and foliar

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All available cucumber (Cucumis sativus L.) cultigens were tested for combining ability for fruit storage ability by crossing them with the gynoecious inbred Gy 14. Fruit weight and firmness were measured before and after storage, and fruits were rated for water loss after storage. The cultigens with the lowest percentage of fruit weight loss during storage were PI 172839, PI 344067, PI 264667, PI 171612, PI 339245, PI 220171, PI 279469, and PI 368550; those with the lowest percentage of loss in fruit firmness were PI 379284, PI 339241, PI 414159, PI 422177, `Regal', PI 109483, `Addis', PI 285603, PI 257486, and `Calypso'. The cultigens demonstrating the least fruit shriveling were `Dasher II', `Sprint 440', `Texas Long', PI 390255, PI 432870, `Pacer', PI 419078, PI 390247, PI 321011, and PI 414158. The 10 best cultigens from the initial screening study, along with the four worst cultigens and six checks, were retested directly (not as F1 progeny) for fruit keeping ability in two storage conditions and at two harvest dates. No significant differences were detected between the two harvest dates and storage conditions.

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Yield was evaluated in 817 plant introduction accessions of cucumber (Cucumis sativus L.) along with 19 check cultivars. The study was conducted in spring and summer seasons of 1997 and 1998 with three replications using recommended horticultural practices and optimized field plot trials. In order to get fruit from each cultigen regardless of sex expression, plants were sprayed with ethrel (2-chloroethyl phosphonic acid) to make them gynoecious. Plots were harvested once-over when 10% of the fruit in a plot were oversize. Data were collected on fruit weight (total, marketable, early and cull), fruit number (total, marketable, early and cull), fruit type, fruit quality, and days to harvest. Total fruit weight for all cultigens ranged from 4 to 214 Mg/ha, with 1 to 40 fruit per plot. Based on statistical analysis, fruit number was the most useful trait for yield evaluation. Stand corrections for yield were not found to be useful. The cultigens with the highest fruit numbers for pickling type were PI 215589, PI 179678, PI 249561, PI 356809, and PI 370643. Highest fruit number for slicing type were PI 344440, PI 422199, and PI 342951. Highest fruit number for middle-eastern type were PI 525150, PI 525153, PI 181910, and PI 534540. Highest fruit number for Oriental trellis type were PI 432849, PI 432866, PI 508455, PI 372893, and PI 532520. Several cultigens produced more than the check cultivars. High-yielding cultigens could be used in breeding programs to improve the yield of cucumber.

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In 1999 and 2000, a total of 27 diploid watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] cultivars and advanced breeding lines (hereafter referred to as cultigens) were evaluated for staminate flower and pollen grain production to assess their potential to serve as pollenizers (pollen source plants) in triploid watermelon production systems. Male reproductive output (staminate flower and pollen production) was quantified during the peak flowering and fruit setting phase of the cultigens under field conditions. The number of staminate flowers produced per plant per day, number of pollen grains produced per flower, and total number of pollen grains produced per plant per day (staminate flowers per plant × pollen grains produced per flower) differed greatly among cultigens (for all tests, P < 0.01). Staminate flower production by cultigens differed by year (P < 0.0029) and days within years (P = 0.0225), but pollen production between years by cultigens was stable (P = 0.4841). Total male reproductive output ranged from 134,206 pollen grains per plant per day for `Jamboree' to 321,905 pollen grains per plant per day for `Summer Flavor 500'. These studies demonstrate the genotypic variability in watermelon male reproductive output potential, and may assist growers in choosing a good diploid pollenizer for triploid watermelon production.

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All available luffa (Luffa aegyptiaca Mill.) cultivars, breeding lines, and plant introduction accessions (collectively referred to as cultigens hereafter) were evaluated at Clinton, N.C., over 3 years. Plants were grown in plots 1.5-m-long on a 1.8-m-high trellis. Border rows and tiers on the sides and ends of the trial were used to reduce the edge effect. Plots were planted in May and evaluated for vine height and sex expression. Fruit were harvested in October to determine fruit number and length after frost killed the vines. Sponges were processed from the fruit and evaluated for seed cell number, wall thickness, sponge strength, fiber denseness, and other quality traits. The tallest vined cultigens were PI 286425 and Fletcher, and the shortest vined were PI 381869 and PI 540921. The highest yielding (sponge number per hectare) cultigens were PI 540921 and PI 391603, and the lowest yielding cultigens were Luffa 30310 and Luffa 97321. Of the cultigens tested, PI 391603 had the longest fruit overall, whereas PI 540921 had the shortest.

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Suitability of commercial production of oriental trellis type cucumber (Cucumis sativus L.) was evaluated using 18 cultivars and breeding lines (referred to as cultigens hereafter). The cultigens (15 oriental trellis and three American slicers) were tested using two systems (trellis and flat bed production) in two seasons (spring and summer) in 1995 at Clinton, N.C. Traits evaluated included total yield, early yield, percentage culls, vine length, leaf area, gynoecious rating, fruit shape, fruit color, fruit length, seed cell size, anthracnose resistance, powdery mildew resistance, and fruit keeping ability. Highest yielding cultigens were `Summer Top', `Tasty Bright', and `Sprint 440'. Those with best fruit quality were `Sprint 440', `Tasty Bright', `Poinsett 76', and `Summer Top'. Most disease resistant was `Poinsett 76'. The best cultigens considering all traits measured were `Sprint 440', `Tasty Bright', and `Summer Top'. Production of cultigens on trellis rather than flat bed resulted in an average increase in total, marketable, and fancy yield of 130%, 160%, and 140%, respectively. Oriental trellis cucumbers can be produced as a less expensive alternative to European greenhouse cucumbers, and to supply consumer demand for this particular product type.

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In 1999 and 2000, a total of 28 diploid watermelon cultigens (released cultivars and advanced breeding lines) were evaluated for staminate flower and pollen grain production to assess their potential to serve as pollenizers (pollen source plants) in triploid watermelon production systems. Male reproductive output (staminate flower and pollen production) was quantified during the peak flowering and fruit setting phase of the cultigens under field conditions. The number of staminate flowers produced per plant per day, number of pollen grains produced per flower, and total number of pollen grains produced per plant per day (staminate flowers per plant x pollen grains produced per flower) differed greatly between cultigens (for all tests, P < 0.01). Staminate flower production by cultigens differed by year (P < 0.0003) and days-within-years (P = 0.0094), but pollen production between years by cultigens was stable (P = 0.3845). Total male reproductive output ranged from 134,206 pollen grains per plant per day for `Jamboree' to 321,905 pollen grains per plant per day for `Summer Flavor 500'. These studies demonstrate the genotypic variability in watermelon male reproductive output potential, and may assist growers in selecting an optimal diploid pollenizer for triploid watermelon production.

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Belly rot, caused by the fungal pathogen Rhizoctonia solani Kühn., is a severe disease in many regions that produce cucumber (Cucumis sativus L.). Annual crop loss to belly rot is commonly 5% to 10%, but losses as high as 80% can occur in individual fields. There are no resistant cultivars, so fungicides are used to provide partial control. Genetic resistance in an acceptable cultivar would be more desirable and economical. Studies were conducted in Summers 1991 and 1992 to screen promising germplasm for belly rot resistance using field and detached-fruit screening methods. In 1991, 105 cultigens (cultivars, breeding lines, and plant introduction accessions) were evaluated for belly rot resistance. The tests were repeated in 1992 with 63 cultigens, including the most resistant cultigens identified in 1991 and appropriate controls. Several cultigens were identified as potential sources of resistance genes. Pickling cucumbers showing resistance included PI 197085, PI 271328, and an F4 selection of PI 197087 × PI 280096. Slicing cucumbers with resistance included `Marketmore 76' and the F1 of Gy 14 × PI 197087. Belly rot resistance was not correlated with other horticultural traits measured, including fruit type, skin type, spine color, and firmness. The resistant cultigens identified should be useful for developing cucumber cultivars with enhanced resistance to Rhizoctonia solani.

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We conducted a field screening of melon (Cucumis melo L.) cultigens to identify potential sources of host-plant resistance to Monosporascus cannonballus Pollack & Uecker. Seed were sown in Speedling trays with inoculated or noninoculated media. Plants were transplanted into a field known to be highly infested with M. cannonballus. Cultigens were arranged in a randomized complete block with three replications in each treatment (fumigated/noninoculated, nonfumigated/inoculated). Vine decline (1 = no symptoms to 5 = dead vines) was rated at 78 and 90 days post-transplanting. Disease symptoms were most severe and occurred earliest in the inoculated, nonfumigated plots. However, natural infection by M. cannonballus occurred in the fumigated plots, as all root samples collected contained perithecia. The majority of cultigens (85%) showed moderate to severe vine decline symptoms. Mean vine decline ratings of melon types from the spring test, ranked from most tolerant to least tolerant, were: Charentais = Ananas = Galia > Misc. = Honeydew = Mixed > US cantaloupe. A Fall test of the most tolerant cultigens showed similar results, in that Ananas and Charentais types had the highest tolerance; however, Galia types performed poorly, which may be due to the different environmental conditions, or differing fruit loads on the vines in the two tests. `Deltex', an Ananas hybrid, showed the highest tolerance based on vine decline ratings in the two tests.

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Production of pickling cucumber (Cucumis sativus L.) requires a significant expenditure of labor and money. Those resources could be better managed if both yield and harvest date could be predicted for a given planting date and production area. The objective of this experiment was to develop a model to simulate growth and yield of pickling cucumbers under field conditions in North Carolina. Detailed measurements of leaf area, branching habit, flowering, fruiting, and dry weight distribution were obtained for the cultigens `Calypso', M 21, `Wis. SMR 18', and WI 2757 for 10 planting dates. Light interception, air temperature, and rainfall were also recorded. There were differences among cultigens and planting dates for time needed to reach certain growth stages. Number of days to reach a given stage generally decreased with later planting dates. Addition of nodes over time to the main stem was linear and the interaction of planting date by cultigen was significant. Number of staminate and pistillate flowers was affected by both cultigen and planting date.

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